netfilter: connlimit: move insertion of new element out of count function

Allows easier code-reuse in followup patches.
Reviewed-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/xt_connlimit.c

@@ -97,13 +97,12 @@ static int count_hlist(struct net *net,
 		       const struct nf_conntrack_tuple *tuple,
 		       const union nf_inet_addr *addr,
 		       const union nf_inet_addr *mask,
-		       u_int8_t family)
+		       u_int8_t family, bool *addit)
 {
 	const struct nf_conntrack_tuple_hash *found;
 	struct xt_connlimit_conn *conn;
 	struct hlist_node *n;
 	struct nf_conn *found_ct;
-	bool addit = true;
 	int matches = 0;
 
 	rcu_read_lock();
@@ -126,7 +125,7 @@ static int count_hlist(struct net *net,
 			 * We should not see tuples twice unless someone hooks
 			 * this into a table without "-p tcp --syn".
 			 */
-			addit = false;
+			*addit = false;
 		} else if (already_closed(found_ct)) {
 			/*
 			 * we do not care about connections which are
@@ -146,18 +145,20 @@ static int count_hlist(struct net *net,
 
 	rcu_read_unlock();
 
-	if (addit) {
-		/* save the new connection in our list */
-		conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
+	return matches;
+}
+
+static bool add_hlist(struct hlist_head *head,
+		      const struct nf_conntrack_tuple *tuple,
+		      const union nf_inet_addr *addr)
+{
+	struct xt_connlimit_conn *conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
 	if (conn == NULL)
-			return -ENOMEM;
+		return false;
 	conn->tuple = *tuple;
 	conn->addr = *addr;
 	hlist_add_head(&conn->node, head);
-		++matches;
-	}
-
-	return matches;
+	return true;
 }
 
 static int count_them(struct net *net,
@@ -170,6 +171,7 @@ static int count_them(struct net *net,
 	struct hlist_head *hhead;
 	int count;
 	u32 hash;
+	bool addit = true;
 
 	if (family == NFPROTO_IPV6)
 		hash = connlimit_iphash6(addr, mask);
@@ -179,7 +181,13 @@ static int count_them(struct net *net,
 	hhead = &data->iphash[hash];
 
 	spin_lock_bh(&data->lock);
-	count = count_hlist(net, hhead, tuple, addr, mask, family);
+	count = count_hlist(net, hhead, tuple, addr, mask, family, &addit);
+	if (addit) {
+		if (add_hlist(hhead, tuple, addr))
+			count++;
+		else
+			count = -ENOMEM;
+	}
 	spin_unlock_bh(&data->lock);
 
 	return count;